Ultima III internal formats

Note: This file was originally found here.

SHAPES.ULT

This file contains 0x50 tiles. All tiles are 16*16 pixels^2. Each tile in stored in CGA-compatible format. The first 0x20 bytes of each tile contain the first bit plane, the following 0x20 bytes contain the second bit plane.

Offset	Length	Purpose
0x0	0x40	tile 0x0
0x40	0x40	tile 0x1
0x80	0x40	tile 0x2
...	...	...
0x13C0	0x40	tile 0x4f

• The Ultima III monochrome, CGA, and EGA tileset

The CGA tileset uses the following structure which is a linear format with interlacing:

• The tile data is organized into two 32-byte planes:
  • Plane 0: Contains even rows (0, 2, 4, 6, 8, 10, 12, 14)
  • Plane 1: Contains odd rows (1, 3, 5, 7, 9, 11, 13, 15)

• Each plane uses CGA linear encoding where one byte encodes 4 pixels using 2 bits per pixel:
  • Bits 7-6: First pixel
  • Bits 5-4: Second pixel
  • Bits 3-2: Third pixel
  • Bits 1-0: Fourth pixel

• Each row consists of 16 pixels encoded in 4 bytes. The 2-bit values map to the CGA palette:
  • 00: Black
  • 01: Cyan
  • 10: Magenta
  • 11: White

The index within this character set is also used to index the XP table. The table repeats every 16 monsters (with 2 rows never used), which explains why such difficult monsters like Floors or Grasses only get you a few XP. (It's not possible to actually kill Lord British or Exodus, but it's fun to see what their XP would be if you could.)

Water	Merchant	1
Grass	Jester	2
Brush	Guard	15
	Lord British	20
	Fighter	8
	Cleric	6
	Wizard	10
	Thief	5
Floor	Orc	3
Chest	Skeleton	4
Horse	Giant	6
	Daemon	8
	Pincher	10
Serpent	Dragon	15
Man-O-War	Balron	20
Ranger	Exodus	5

CHARSET.ULT

This file contains the 0x80 characters that make up the U3 font. All characters are 8*8 pixels^2. Each character in stored in CGA-compatible format. The first 0x8 bytes of each character contain the first bit plane, the following 0x8 bytes contain the second bit plane.

Offset	Length	Purpose
0x0	0x10	character 0x0
0x10	0x10	character 0x1
...	...	...
0x7F0	0x10	character 0x7F

SOSARIA.ULT

This file contains the world map and information about the game world state.

Offset	Length	Purpose
0x0	0x1000	64*64 world map
0x1000	0x180	not used
0x1180	0x20	tile number of monster 1-32; divide by 4 to get real tile number
0x11A0	0x20	tile number of floor under monster 1-32; divide by 4 to get real tile number
0x11C0	0x20	x coordinate of monster 1-32
0x11E0	0x20	y coordinate of monster 1-32
0x1200	0x20	movement flag of monster 1-32
0x1220	0x1	x coordinate of whirlpool
0x1221	0x1	y coordinate of whirlpool
0x1222	0x1	signed byte to add to x coordinate of whirlpool; possible values: 0, 1, 0xFF
0x1223	0x1	signed byte to add to y coordinate of whirlpool; possible values: 0, 1, 0xFF
0x1224	0x1	current phase of left moon; ranges from 0-7
0x1225	0x1	current phase of right moon; ranges from 0-7
0x1226	0x1	current sub-phase of left moon; ranges from 0-0xB
0x1227	0x1	current sub-phase of right moon; ranges from 0-3

Tiles

Tile #	Notes
0x00	Water
0x04	Grass
0x08	Brush
0x0C	Forest
0x10	Mountains
0x14	Dungeon
0x18	Towne
0x1C	Castle
0x20	Floor
0x24	Chest
0x28	Horse
0x2C	Frigate
0x30	Whirlpool
0x34	Serpent
0x38	Man-o-War
0x3C	Pirate
0x40	Merchant
0x44	Jester
0x48	Guard
0x4C	Lord British
0x50	Fighter
0x54	Cleric
0x58	Wizard
0x5C	Thief
0x60	Orc
0x64	Skeleton
0x68	Giant
0x6C	Daemon
0x70	Pincher
0x74	Dragon
0x78	Balron
0x7C	Exodus
0x80	Force Field
0x84	Lava
0x88	Moon Gate
0x8C	Wall
0x90	Void
0x94	Wall (Space)
0x98	A
0x9C	B
0xA0	C
0xA4	D
0xA8	E
0xAC	F
0xB0	G
0xB4	H
0xB8	I
0xBC	V
0xC0	Y
0xC4	L
0xC8	M
0xCC	N
0xD0	O
0xD4	P
0xD8	W
0xDC	R
0xE0	S
0xE4	T
0xE8	Snake (tail)
0xEC	Snake (head)
0xF0	Magic
0xF4	Fire
0xF8	Shrine
0xFC	Ranger

Monsters, horses, ships, chests

U3 stores the location of these objects by writing them directly into the map.

Monsters

Monsters are stored as basetile_number*4. The map tile under the monster is stored in the table at 0x11A0.

Horses

Horses are stored as 0x28 == horse_tile*4. The tile under the horse can only be 0x1, because you can only dismount a horse on a grass tile.

Ships

Ships are stored as 0x2C == ship_tile*4. The tile under the ship can only be 0x0.

Chests

The map tile under the chest is encoded in the lowest 2 bits of the tile: 0x24 == chest_tile*4 + 0 --> chest on bricks (tile 0x8) 0x25 == chest_tile*4 + 1 --> chest on grass (tile 0x1) 0x26 == chest_tile*4 + 2 --> chest on forest (tile 0x2) 0x27 == chest_tile*4 + 3 --> chest on deep forest (tile 0x3) Monsters can't walk onto chests, so there can only be one chest per map square.

Moon phases and sub-phases

Each turn, both sub-phases are decremented. When a sub-phase reaches -1, it is reset to 0xB/3, and the corresponding phase is incremented. The phases are the numbers displayed on the upper border of the game world window.

EXODUS.BIN

This is the file executable.

Offset	Length (in bytes)	Purpose
0x0	5600	???
0x015e1	4	x/y coordinates of castles. LCB and Castle Death (two bytes, one for x and one for y)
0x015e5	20	x/y coordinates of towns (two bytes, one for x and one for y)
0x015f9	14	x/y coordinates of dungeons (two bytes, one for x and one for y)
0x184d	8	moongate x-coordinates (one byte for each moongate)
0x1855	8	moongate y-coordinates (one byte for each moongate)
0x6566	335	list of null terminated strings for the (L)ook command
0x7445	2	xy-coordinates for Exotic Weapons (1 byte for x and one byte for y)
0x7450	2	xy-coordinates for Exotic Armour (1 byte for x and one byte for y)

DEMO.ULT

This file contains the 19*6 map displayed in the main menu. Each byte represents a tile.

MOVES.ULT

This file contains the animation script for the main menu map.

Offset	Length	Purpose
0x0	0x200	command table
0x200	0x200	data table

ROSTER.ULT

This file stores the infomation about all the characters the player has created.

Offset	Length	Purpose
0x0	0x40	character record 1
0x40	0x40	character record 2
...	...	...
0x4C0	0x40	character record 20

Character record format

NOTE: BCD = binary coded decimal (two digits per byte).

Offset	Length	Purpose
0x0	0xA	character name; ASCII string, 0-terminated. Padded with 0's.
0xA	0x4	?
0xE	0x1	marks and cards; bit 0-7 = love, sol, moon, death, force, fire, snake, kings
0xF	0x1	number of torches; BCD
0x10	0x1	0x0 = character is not in party, 0xFF = character is in party
0x11	0x1	status; ASCII character: G,P,D,A
0x12	0x1	strength; BCD
0x13	0x1	dexterity; BCD
0x14	0x1	intelligence; BCD
0x15	0x1	wisdom; BCD
0x16	0x1	race; ASCII character: E,D,F,H,B
0x17	0x1	class; ASCII character: W,R,T,I,A,D,F,L,C,B
0x18	0x1	gender; ASCII character: M,F,O
0x19	0x1	current magic points; BCD
0x1A	0x2	current hit points; BCD
0x1C	0x2	maximum hit points; BCD
0x1E	0x2	experience points; BCD
0x20	0x1	sub-morsels; BCD
0x21	0x2	food; BCD
0x23	0x2	gold; BCD
0x25	0x1	gems; BCD
0x26	0x1	keys; BCD
0x27	0x1	powders; BCD
0x28	0x1	currently worn armor
0x29	0x7	how many of each armor type; BCD
0x30	0x1	currently readied weapon
0x31	0xF	how many of each weapon type; BCD

Sub-morsels

This field contains 2 digits (those behind the decimal point) of the food field. On the surface, the game subtracts 10 from this field during every turn (remember that it contains a BCD). Everywhere else, the game subtracts 10 every 4 turns.

Weapon types

Offset	Letter	Name
0x31	B	Dagger
0x32	C	Mace
0x33	D	Sling
0x34	E	Axe
0x35	F	Bow
0x36	G	Sword
0x37	H	2H Sword
0x38	I	+2 Axe
0x39	J	+2 Bow
0x3A	K	+2 Sword
0x3B	L	Gloves
0x3C	M	+4 Axe
0x3D	N	+4 Bow
0x3E	O	+4 Sword
0x3F	P	Exotic Weapon

Armor types

Offset	Letter	Name
0x29	B	Cloth
0x2A	C	Leather
0x2B	D	Chain
0x2C	E	Plate
0x2D	F	+2 Chain
0x2E	G	+2 Plate
0x2F	H	Exotic Armor

PARTY.ULT

This file contains information about the current party. BCD = binary coded decimal (two digits per byte).

Offset	Length	Purpose
0x0	0x1	mode of transportation; 0xA = horse, 0xB = ship, 0x3F = on foot
0x1	0x1	?
0x2	0x1	party location
0x3	0x4	number of moves; BCD
0x7	0x1	number of characters in the party
0x8	0x1	x coordinate of party (on Sosarian map)
0x9	0x1	y coordinate of party (on Sosarian map)
0xA	0x4	number of PC in slot 1-4 (party order)
0xE	0x4	?
0x12	0x40	character record for PC 1
0x52	0x40	character record for PC 2
0x92	0x40	character record for PC 3
0xD2	0x40	character record for PC 4

Party location

Value	Location
0	Sosaria
1	dungeon
2	towne
3	castle (LB's Castle, Castle Death)
4	shrine, fountain, mark
0x80	combat
0xF0	talking to merchant
0xFF	Ambrosia

Note: You can only save your game in Sosaria, so the party location field in the file is always 0.

.ULT files (town maps)

These files contain the map and "dialog" for each town. There are 32 NPC's in every town. (?)

BRITISH.ULT	Lord British's castle
DAWN.ULT	Dawn
DEATH.ULT	Death Gulch
DEVIL.ULT	Devil Guard
EXODUS.ULT	Exodus (Castle Death)
FAWN.ULT	Fawn
GREY.ULT	Grey
LCB.ULT	Britain
MONTOR_E.ULT	Montor East
MONTOR_W.ULT	Montor West
MOON.ULT	Moon
YEW.ULT	Yew

Map format

Offset	Length	Purpose
0x0	0x1000	64*64 town map
0x1000	n*0x2	sign text offsets; n <= 8, add 0x1000 to get the real offset
0x1000+n*0x2	variable	sign texts and dialog; all texts are 0-terminated ASCII strings
0x1180	0x20	tile number for each NPC; divide by 4 to get real tile number
0x11A0	0x20	tile number of floor under each NPC; divide by 4 to get real tile number
0x11C0	0x20	starting x coordinate of each NPC
0x11E0	0x20	starting y coordinate of each NPC
0x1200	0x20	movement flag + dialog number
0x1220	0x8	not used

Movement flag + dialog number

(byte >> 4) == 0 --> NPC walks around

(byte >> 4) == 4 --> NPC doesn't move

(byte >> 4) == 8 --> NPC is a merchant

(byte >> 4) == 0xC --> NPC attacks party

(byte % 0xF) == sentence number

Still unknown: 0x85, 0x86 (?)

.ULT files (dungeon maps)

These files contain the dungeon maps and sign texts.

DARDIN.ULT	Dardin's Pit
FIRE.ULT	Dungeon of Fire
M.ULT	Dungeon of Doom
MINE.ULT	Mines of Morinia
P.ULT	Dungeon of the Snake
PERINIAN.ULT	Perinian Depths
TIME.ULT	Dungeon of Time

Map format

Offset	Length	Purpose
0x0	0x100	16*16 map of level 1
0x100	0x100	16*16 map of level 2
...	...	...
0x700	0x100	16*16 map of level 8
0x800	n*0x2	sign text offsets; n = 8, add 0x800 to get the real offset
0x810	0x80	sign texts; every sign text is a null-terminated ASCII string

There is at most one sign per dungeon level. To find out the text for a sign, use (dungeon_level-1) as an index into the table at 0x800.

.ULT files (conflict maps)

These files contain the 11*11 conflict maps.

CNFLCT_A.ULT

CNFLCT_B.ULT

CNFLCT_C.ULT

CNFLCT_F.ULT

CNFLCT_G.ULT grasslands

CNFLCT_M.ULT

CNFLCT_Q.ULT

CNFLCT_R.ULT

CNFLCT_S.ULT

Map format

Offset	Length	Purpose
0x0	0x79	11*11 map; each byte represents one tile
0x79	0x7	?
0x80	0x8	starting x coordinates for monsters 1-8
0x88	0x8	starting y coordinates for monsters 1-8
0x90	0x8	not used
0x98	0x8	not used
0xA0	0x4	starting x coordinates for PC's 1-4
0xA4	0x4	starting y coordinates for PC's 1-4
0xA8	0x4	not used
0xAC	0x4	not used

U3 uses the 8 bytes at offset 0x90 (in memory) to store the tiles under monster 1-8. U3 uses the 8 bytes at offset 0x98 (in memory) to store the hit points of monster 1-8. U3 uses the 4 bytes at offset 0xA8 (in memory) to store the tiles under PC 1-4. U3 uses the 4 bytes at offset 0xAC (in memory) to store the base tiles for PC 1-4. U3 doesn't use the values stored at these locations in the conflict files.

.IMG files

Each of these files contains an 11*11 tile image. Each byte represents a tile number.

BRAND.IMG	Brand
FOUNTAIN.IMG	Fountain
SHRINE.IMG	Ambrosian shrine
TIME.IMG	Time Lord

Further Notes

I'm pretty sure that U3 doesn't save the wind direction.

External Links

• Original copy of this article
• Ultimatrix website
• Decoding of the roster file format
• Transcript of the NPC dialogue

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Technical Details
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